1. Field of Invention
The invention relates to an image duplicating apparatus having such as a laser printer mechanism and to a storage medium that stores programs for controlling the image duplicating apparatus.
2. Description of Related Art
Currently, some facsimile machines have duplicating functions to duplicate original images onto a recording paper, similar to office-use copying machines, in addition to the ordinary facsimile functions to send and receive the facsimile images. In such facsimile machines having the duplicating functions, the laser printer mechanism is being adopted instead of the thermal printer mechanism to meet the demands for printing speed.
The facsimile machines that perform duplicating using the laser printer type, include a line image sensor that reads images on a document line-by-line in the main -scanning direction while the document is being conveyed, and a laser printer mechanism that consecutively transfers toner images in the sub scanning direction, onto a recording paper to be discharged thereafter. In the above-described structure, the printing speed by the laser printer mechanism tends to be faster than the reading speed of the line image sensor. Therefore, a page memory capable of storing image data for one page is mounted on the facsimile machine so that the input/output processing of the image data can be performed between the line image sensor and the laser printer mechanism.
In some of other facsimile machines having the printer mechanism other than laser printer, the reading operation and printing operation are controlled so that they are synchronized according to the image data stored in a memory. For example, when any image data is not stored in the memory, the printing operation is temporarily stopped until the image data is stored in the memory to a certain extent (amount). After the image data is stored in the memory to a certain extent, the printing operation is started again, as linked with the reading operation.
However, the conventional facsimile machines having duplicating functions using the laser printer type need to have a page memory capable of storing the image data for one page due to the difference between the reading and printing speeds. If the size of the memory is increased, its cost is increased accordingly.
The conventional facsimile machines that have a printer mechanism other than a laser printer that control the reading and printing operations so that they are synchronized, the input/output processing of the image data may be performed via a memory with the smaller size than the page memory. Therefore, the problems with respect to the increase in the costs of the memory will be settled. However, complicated adjustments are required for controlling the reading and printing operations. In addition, the downtime in which the printing operation is not performed or is interrupted, is generated during the time in which the images are read from an original and are formed onto the recording paper. Therefore, the time required for the whole duplicating processing will not be shortened due to the downtime or the interruption of the printing operation, even though the printing operation does not take as much time when the image data is stored in the memory and the printing operation is not interrupted.
One aspect of the invention is to provide an image duplicating apparatus capable of performing the duplicating operation with its whole operation time shortened by the simple speed adjustments, without increasing the size of the memory as much as possible and its costs. Another aspect of the invention is to provide a storage medium that stores programs for controlling the image duplicating apparatus.
According to one aspect of the invention, there is provided an image duplicating apparatus having an image reading device that reads images from an original line-by-line in the main scanning direction and a printing device that consecutively forms the images line-by-line onto a recording paper in the sub scanning direction. The image duplicating apparatus performs input/output processing between the image reading device and the printing device via a memory to duplicate the images read from the original onto a recording paper. The image duplicating apparatus includes a line data writing controlling device that writes the image line data obtained from the image reading device after having the input processing, line-by-line, into the memory and that retains at least one line of the image line data in the memory, a written line information obtaining device that obtains the written line information as to the condition of at least two lines of the image line data written into the memory by the line data writing controlling device, and a line data reading controlling device that reads out the one complete line of the image line data from the memory upon the receipt of the data output request from the printing device, referring to the written line information obtained by the written line information obtaining device and outputs the image line data to the printing device.
In the image duplicating apparatus, the image line data is written into the memory line-by-line, and at least one line of the image line data is retained in the memory. The one complete line of the image line data is read out from the memory and is used for printing processing. Therefore, the image duplicating apparatus does not have to have a page memory capable of storing the image data for one page, but the input/output processing may be performed though a memory into which at least two lines of the image line data can be written or from which it can be read out. Consequently, the size of the memory mounted on the image duplicating apparatus is not increased as much as possible, and also its costs are not increased. Even when the time required to print one line of the image line data is shorter than that required to read one line of the image data, that is, when the cycle of reading the image line data from the line buffer memory is faster than that of writing the image line data thereinto, the one complete line of the image line data will always be retained in the memory except at the start of the duplicating operations. Therefore, the printing operations may be performed without any stops or interruption during the duplicating operations, and the time required for the duplicating operations can be shortened without the printing and reading time for one line of the image line data being adjusted.
Also in the invention, the speed of reading the images line-by-line in the main scanning direction by the image reading device (conveying the original document) and the speed of consecutively forming images line-by-line in the sub scanning direction by the printing device (conveying a recording medium), are adjusted so that they become equal.
Since the reading and printing speeds are adjusted so that they become equal, the images obtained by reading from the original line-by-line in the main scanning direction, are formed onto a recording paper in the sub scanning direction approximately at fall scale.
Further in the invention, the speed of reading the images line-by-line in the main scanning direction by the image reading device and the speed of consecutively forming images line-by-line in the sub scanning direction by the printing device, are adjustable so that they are relatively varied.
Since the reading and printing speeds are adjustable so that they are relatively varied, the images obtained by reading from the original line-by-line in the main scanning direction, are formed onto the recording paper while being enlarged or reduced in the sub scanning direction.
In the image duplicating apparatus of the invention, when the result that any complete line of the image line data does not exist in the memory, is obtained by referring to the written line information obtained by the written line information obtaining device, upon the receipt of the data output request from the printing device, the line data reading controlling device outputs pseudo-data for the image line data.
Even when any complete line of the image line data does not exist in the memory, the printing processing may be performed based on the pseudo-data instead of the image line data. At the start of the duplicating processing, one complete line of the image line data has not been yet written into the memory. However, the printing processing is performed based on the pseudo-data until one line of the image line data is completely written into the memory. Therefore, the duplicating processing is performed effectively without the printing processing being stopped or interrupted.
According to another aspect of the invention, there is provided a storage medium that stores programs for controlling an image duplicating apparatus having an image reading device that reads images from an original line-by-line in the main scanning direction and a printing device that consecutively forms the images line-by-line onto a recording paper in the sub scanning direction, and performing input/output processing between the image reading device and the printing device via a memory to duplicate the images read from the original onto a recording paper. The storage medium may include a line data writing controlling program for writing the image line data obtained from the image reading device after having the input processing, line-by-line into the memory and for retaining at least one line of the image line data in the memory, a written line information obtaining program for obtaining the written line information as to the condition of at least two lines of the image line data written into the memory based on the line data writing controlling program, and a line data reading controlling program for reading out the one complete line of the image line data from the memory upon the receipt of the data output request from the printing device, referring to the written line information obtained based on the written line information obtaining program and for outputting the image line data to the printing device.
By activating the CPU based on the stored program, the image duplicating apparatus of the invention can be realized.